mirror of
https://github.com/larsimmisch/pyalsaaudio.git
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70 lines
1.9 KiB
Python
Executable File
70 lines
1.9 KiB
Python
Executable File
#!/usr/bin/env python
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## recordtest.py
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##
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## This is an example of a simple sound capture script.
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##
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## The script opens an ALSA pcm device for sound capture, sets
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## various attributes of the capture, and reads in a loop,
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## writing the data to standard out.
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##
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## To test it out do the following:
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## python recordtest.py out.raw # talk to the microphone
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## aplay -r 8000 -f S16_LE -c 1 out.raw
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#!/usr/bin/env python
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from __future__ import print_function
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import sys
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import time
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import getopt
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import alsaaudio
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def usage():
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print('usage: recordtest.py [-d <device>] <file>', file=sys.stderr)
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sys.exit(2)
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if __name__ == '__main__':
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device = 'default'
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opts, args = getopt.getopt(sys.argv[1:], 'd:')
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for o, a in opts:
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if o == '-d':
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device = a
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if not args:
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usage()
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f = open(args[0], 'wb')
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# Open the device in nonblocking capture mode. The last argument could
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# just as well have been zero for blocking mode. Then we could have
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# left out the sleep call in the bottom of the loop
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inp = alsaaudio.PCM(alsaaudio.PCM_CAPTURE, alsaaudio.PCM_NONBLOCK, device=device)
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# Set attributes: Mono, 44100 Hz, 16 bit little endian samples
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inp.setchannels(1)
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inp.setrate(44100)
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inp.setformat(alsaaudio.PCM_FORMAT_S16_LE)
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# The period size controls the internal number of frames per period.
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# The significance of this parameter is documented in the ALSA api.
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# For our purposes, it is suficcient to know that reads from the device
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# will return this many frames. Each frame being 2 bytes long.
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# This means that the reads below will return either 320 bytes of data
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# or 0 bytes of data. The latter is possible because we are in nonblocking
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# mode.
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inp.setperiodsize(160)
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loops = 1000000
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while loops > 0:
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loops -= 1
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# Read data from device
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l, data = inp.read()
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if l:
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f.write(data)
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time.sleep(.001)
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